Posted on 2014-11-15 in linux
I used Linux for years without bothering to find out how the chmod numbers worked. Turns out its very simple, and much faster to use than the "human" way of -u, -o, -g.
4 read (r) 2 write (w) 1 execute (x) Position 1: Owner Position 2: Group Position 3: Everyone
So: 640 is Owner=Read (4+2), Group=Read (4), Everyone=None (0)